Call of Duty 3 Codes -

Unlock All Levels and Pictures
Hold then press , , , , , on D-pad while at the Chapter Select Screen. This effect only remains until you restart your console.

Achievements
Complete each achievement to get the allotted gamerscore:

A War Hero (30) - Capture the final objective in the game mode War. Must be a ranked match. (Multiplayer)
Allergic to Bullets (25) - Avoid getting hit more than 30 times during a mission.
American Infantryman (20) - Complete two missions as an American soldier.
Assault Trooper (15) - Complete a mission by firing only assault rifles. Melee attacks don't count.
Basic Training (5) - Complete the basic training in the beginning of Saint Lo.5.
Battlefield Scavenger (15) - Complete a mission by firing only German weapons. Melee attacks don't count.
Big Air (25) - Find a big jump and catch some air.
British Commando (20) - Complete two missions as a British soldier.
Canadian Highlander (10) - Complete two missions as a Canadian soldier.
Captain (40) - Receive 2000 total points in ranked matches. (Multiplayer)
Close Quarter Combatant (100) - Complete a mission without firing a round. Player can make use of melee attacks and hand grenades.
Colonel (80) - Receive 20000 total points in ranked matches. (Multiplayer)
Conservationist (20) - Complete a mission using less than 300 rounds of ammunition.
Doc (30) - Revive 10 of your teammates in a ranked match without getting a teamkill. (Multiplayer)
EXTREME! (25) - Found a big jump and caught some air!
General (120) - Receive 40000 total points in ranked matches. (Multiplayer)
Grizzled Veteran (150) - Complete the Single Player Campaign on Veteran difficulty.
Hot Potato (25) - Pick up and return 5 live grenades.
Lieutenant (20) - Receive 200 total points in ranked matches. (Multiplayer)
Major (60) - Receive 8000 total points in ranked matches. (Multiplayer)
Polish Tanker (15) - Complete two missions as a Polish soldier.
Purple Heart (5) - For perserverence despite grevious injuries.
Rifleman (15) - Complete a mission by firing only bolt action rifles. Melee attacks don't count.
Still Ticking (30) - Complete a mission without dying or using checkpoints.
Supply Officer (15) - Supply ammunition to at least 20 friendly soldiers in a single ranked match. (Multiplayer)
Victory Medal (30) - Be the player with the highest score and on the winning team in a ranked match. (Multiplayer)
Won the War (80) - Complete the single player campaign on any difficulty setting.